A5008787397- Advanced Frequency and Time Standards
- Acoustic Wave Resonator Technologies
- Advanced Fiber Laser Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Gyrotron and Vacuum Electronics Research
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Noncommutative and Quantum Gravity Theories
- Geophysics and Sensor Technology
- Superconducting and THz Device Technology
- Advanced MEMS and NEMS Technologies
- Black Holes and Theoretical Physics
- Microwave and Dielectric Measurement Techniques
- Semiconductor Lasers and Optical Devices
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Spectroscopy and Laser Applications
- Advanced Electrical Measurement Techniques
- Quantum, superfluid, helium dynamics
The University of Western Australia
2015-2024
Quantum (Australia)
2022-2024
ARC Centre of Excellence for Engineered Quantum Systems
2013-2022
Panasonic (United States)
2022
ARC Centre of Excellence for Dark Matter Particle Physics
2021
National Institute of Standards and Technology
2005-2019
Joint Institute for Nuclear Research
1988-2017
National University Zaporizhzhia Polytechnic
2015
Université de Limoges
2002
Centre de Recherche en Astronomie Astrophysique et Géophysique
1995
A new approach to N=2 supersymmetry based on the concept of harmonic superspace is proposed and used give an unconstrained superfield geometric description super Yang-Mills supergravity theories as well matter hypermultiplets. The has independent coordinates, in addition usual ones, isospinor harmonics ui+or- sphere SU(2)/U(1). role relate SU(2) group realised component fields a U(1) acting relevant superfields. Their introduction makes it possible SU(2)-covariantise notion Grassmann...
Recent progress in observing and manipulating mechanical oscillators at quantum regime provides new opportunities of studying fundamental physics, for example to search low energy signatures gravity. For example, it was recently proposed that such devices can be used test gravity effects, by detecting the change $[\stackrel{^}{x},\stackrel{^}{p}]$ commutation relation could result from corrections. We show a correction results dependence resonant frequency oscillator on its amplitude, which...
The standard model axion seesaw Higgs portal inflation (SMASH) is a well-motivated, self-contained description of particle physics that predicts dark matter particles to exist within the mass range 50 200 micro–electron volts. Scanning these masses requires an haloscope operate under constant magnetic field between 12 and 48 gigahertz. ORGAN (Oscillating Resonant Group AxioN) experiment (in Perth, Australia) microwave cavity aims search majority predicted by SMASH model. Our initial phase 1a...
We report the results of Phase 1b ORGAN experiment, a microwave cavity haloscope searching for dark matter axions in $107.42--111.93\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{eV}$ mass range. The search excludes with two-photon coupling ${g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}\ensuremath{\ge}4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ 95% confidence interval, setting best upper bound to date and required sensitivity exclude...
A high- $Q$ niobium resonant mass gravitational radiation antenna with a superconducting parametric transducer and noncontacting readout is shown to achieve noise temperature of about 2 mK using zero order predictor filter. The predicted intrinsic cold damping confirmed, along backaction limits on the sensitivity. While has highest factor lowest ever observed in full scale antenna, possibility further improvements demonstrated.
A concept of interferometric measurements has been applied to the development ultra-sensitive microwave noise measurement systems. These systems are capable reaching a performance limited only by thermal fluctuations in their lossy components. The floor real time system measured be equal -193 dBc/Hz at Fourier frequencies above 1 kHz. This is 40 dB better than that conventional and allowed first experimental evidence intrinsic phase isolators circulators. Microwave frequency discriminators...
We report relativity tests based on data from two simultaneous Michelson-Morley experiments, spanning a period of more than 1 yr. Both were actively rotated turntables. One (in Berlin, Germany) uses optical Fabry-Perot resonators made fused silica; the other Perth, Australia) microwave whispering-gallery sapphire resonators. Within standard model extension, we obtain limits Lorentz violation for electrons (5 coefficients) and photons (8) at levels down to ${10}^{\ensuremath{-}16}$, improved...
We present the first results from a rotating Michelson-Morley experiment that uses two orthogonally orientated cryogenic sapphire resonator oscillators operating in whispering gallery modes near 10 GHz. The is used to test for violations of Lorentz invariance framework photon sector standard model extension (SME), as well isotropy term Robertson-Mansouri-Sexl (RMS) framework. In SME we set new bound on previously unmeasured kappa(ZZ)(e-) component 2.1(5.7) x 10(-14), and more stringent...
The low-noise synthesis of a harmonic comb microwave frequencies using 1 GHz femtosecond-laser-based synthesiser that is referenced to cavity-stabilised laser demonstrated. residual phase noise ∼−110 dBc/Hz at Hz offset from the 10 harmonic. Phase measured with an interferometric measurement system having low sensitivity AM.
We review the techniques used in design and construction of cryogenic sapphire oscillators at University Western Australia over 18 year history project. describe project from its beginnings when were first developed as low-noise transducers for gravitational wave detection. Specifically, we that applied to an interrogation oscillator PHARAO Cs atomic clock CNES, Toulouse France, 2006 four high performance use NMIJ NICT, Japan, well a permanent secondary frequency standard laboratory UWA....
Abstract Lorentz symmetry is a foundational property of modern physics, underlying the standard model particles and general relativity. It anticipated that these two theories are low-energy approximations single theory unified consistent at Planck scale. Many unifying proposals allow to be broken, with observable effects appearing Planck-suppressed levels; thus, precision tests invariance needed assess guide theoretical efforts. Here we use ultrastable oscillator frequency sources perform...
Low-loss, high frequency acoustic resonators cooled to millikelvin temperatures are a topic of great interest for application hybrid quantum systems. When 20 mK, we show that resonant phonon modes in bulk wave quartz resonator demonstrate exceptionally low loss (with Q-factors order billions) at frequencies 15.6 and 65.4 MHz, with maximum f · Q product 7.8 × 1016 Hz. Given this result, the Q-factor such devices near ground state can be four orders magnitude better than previously attained....
Miniature atomic clocks based on coherent population trapping (CPT) states in thermal atoms are an important component many field applications, particularly where satellite frequency standards not accessible. Cold-atom CPT promise improved accuracy and stability over existing commercial technologies. Here we demonstrate a cold-atom clock ${}^{87}$Rb using high-contrast double-$\ensuremath{\Lambda}$ configuration. Doppler shifts explained simple model canceled by interrogating the with...
We investigate the response of palladium-cobalt bi-layer thin films to hydrogen charging at atmospheric pressure for spintronic applications. find that absorption by palladium layer results in narrowing and shifting ferromagnetic resonance line material. explain observed phenomena as originating from reduction spin pumping effect variation magnetic anisotropy cobalt film through an interface effect. The shift frequency or field is easiest detect. utilize it demonstrate functionality a sensor.
This work describes the operation of a High Frequency Gravitational Wave detector based on cryogenic Bulk Acoustic (BAW) cavity and reports observation rare events during 153 days over two seperate experimental runs (Run 1 Run 2). In both 2 modes were simultaneously monitored. Across runs, 3rd overtone fast shear mode (3B) operating at 5.506 MHz was monitored, while in second chosen to be 5th OT slow (5C) 8.392 MHz. However, selected closer frequency first mode, (3C) 4.993 Two strong...
We present a way to search for light scalar dark matter (DM), seeking exploit putative coupling between fields and fundamental constants, by searching frequency modulations in direct comparisons stable oscillators. Specifically we compare Cryogenic Sapphire Oscillator (CSO), Hydrogen Maser (HM) atomic oscillator bulk acoustic wave quartz (OCXO). This work includes the first calculation of dependence oscillators on variations demonstration that they can be sensitive tool DM experiments....
The dielectric properties of a single crystal rutile (TiO2) resonator have been measured using whispering gallery modes. Q factors and resonant frequencies were from 300 to 10 K. as high 104, 105, 107 obtained at 300, 80, K, respectively. Using the mode technique we determined accurately loss tangent constant monocrystalline much more sensitive measurements than previously reported. We show that exhibits anisotropy in both permittivity over range
We describe the performance characteristics and frequency measurements of two high-accuracy high-stability laser-cooled atomic standards. One is a 657-nm (456-THz) reference using magneto-optically trapped Ca atoms, other 282-nm (1064-THz) based on single Hg/sup +/ ion confined in an RF-Paul trap. A femtosecond mode-locked laser combined with nonlinear microstructure fiber produces broad stable comb optical modes that used to measure frequencies lasers locked The measurement system...
Excess phase noise is observed in the spectrum of microwave signal extracted from a photodetector illuminated by train ultrashort light pulses femtosecond laser. This affects stability frequency transfer optical to domains with Some contributions excess are related intrinsic beam-pointing fluctuations laser and power detected light. These factors contribute at harmonics pulse repetition rate due power-to-phase conversion photodetector, spatially dependent time delays, photodiode...
We present new results from our test of Lorentz invariance, which compares two orthogonal cryogenic sapphire microwave oscillators rotating in the lab. have now acquired over 1 year data, allowing us to avoid short data set approximation (less than year) that assumes no cancellation occurs between ${\stackrel{\texttildelow{}}{\ensuremath{\kappa}}}_{e\ensuremath{-}}$ and ${\stackrel{\texttildelow{}}{\ensuremath{\kappa}}}_{o+}$ parameters photon sector standard model extension. Thus, we are...
This work demonstrates that ultra-low phase-noise oscillators with a single-sideband spectral density approaching -160 dBc/Hz at Fourier frequency of 1 kHz can be constructed microwave frequencies (8 to 10 GHz). Such noise performance has been achieved by locking conventional loop oscillator temperature-stabilized sapphire dielectric resonator operating relatively high level dissipated power ( <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Atomic clocks based on coherent population trapping (CPT) are of great interest for portable applications, due to their high performance, low power requirements, and potential miniaturization. Slow frequency drift, however, limits holdover ability long time scales. This study reports a CPT clock that minimizes long-term with fractional stability $3\ifmmode\times\else\texttimes\fi{}{10}^{-13}$ over the span an hour---ten times as good previous clocks. After successful shrinking laser-cooling...
Using the technique of point source atom interferometry, we characterize sensitivity a multi-axis gyroscope based on free-space Raman interrogation single cold atoms in glass vacuum cell. The instrument simultaneously measures acceleration direction laser beams and component rotation vector plane perpendicular to that direction. We sensitivities for magnitude measurement, which are 0.033 $^{\circ}/\mathrm{s}$ 0.27 $^{\circ}$ with one second averaging time, respectively. could be improved by...
This paper presents the results of observations detectors participating in International Gravitational Event Collaboration (IGEC) from 1997 to 2000 and reviews data analysis methods. The is designed search for coincident excitations multiple detectors. set analyzed this article covers a longer period more complete than that given previous reports. current accurate determining false dismissal probability time coincidence it optimizes with respect target amplitude direction signal. statistics...